/Engine/Source/Runtime/SlateCore/Public/Layout/SlateRotatedRect.h
Stores a rectangle that has been transformed by an arbitrary render transform. We provide a ctor that does the work common to slate drawing, but you could technically create this any way you want.
struct FSlateRotatedRect
FVector2f
ExtentX
Transformed X extent (right-left).
FVector2f
ExtentY
Transformed Y extent (bottom-top).
FVector2f
TopLeft
Transformed Top-left corner.